Study on Stability of Water-Based Siloxane Hydrophobic Emulsions

Stability of emulsion structure has to be considered and well controlled during synthesis of hydrophobic water-based emulsions. Due to its critical impact on covering ability and adhesion of hydrophobic coating to the top layer of concrete surfaces. Therein, emulsion composition design, as well as proportion of selected raw materials, are the parameters responsible for the achievement of high emulsion stability. Theoretical computations of hydrophilic-lipophilic balance (HLB) were completed in this research to evaluate the stability of water-based emulsion with incorporated emulsifying polyvinyl alcohol (PVA) and silicone hydrophobic agents (SHA). Using Davies’ method, which considers calculating a value based on the chemical groups of the molecule, PVA and SHA meet all requirements to produce highly stable emulsions. Griffin’s method is based on calculating values for different regions of the molecule and demonstrates that the highest stability of “oil in water” emulsion can be achieved using low molecular weight PVA (up to 15000). As the molecular weight of PVA increases, the HLB drops, which results in reduction of emulsion stability and lifetime. ξ-potential ranges were calculated for the investigated emulsions, prepared using different approaches. The results showed that the emulsions with ξ-potential range of < –35 mV and > 50 mV have the highest stability of emulsion structure.

M.I. KOZHUKHOVA^1,2, Candidate of Sciences (Engineering) (This email address is being protected from spambots. You need JavaScript enabled to view it.);
K.G. SOBOLEV^1,2, PhD (This email address is being protected from spambots. You need JavaScript enabled to view it.);
I.L. CHULKOVA³, Doctor of Sciences (Engineering) (This email address is being protected from spambots. You need JavaScript enabled to view it.);
V.V. STROKOVA¹, Doctor of Sciences (Engineering) (This email address is being protected from spambots. You need JavaScript enabled to view it.) 

¹ Belgorod State Technological University named after V.G. Shukhov (46, Kostyukova Street, Belgorod, 308012, Russian Federation) 
² University of Wisconsin-Milwaukee (3200, N. Kramer St., Milwaukee 53211, Wisconsin, USA) 
³ The Siberian Automobile and Highway University (5, Mira Avenue, Omsk, 644080, Russian Federation)

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